The present invention relates to a breast implant system which allows the shape of a breast implant to be varied after its implantation in the patient's body. The present invention particularly improves the breast implant system described in international patent application no. PCT/EP2009/000622.
Breast implants are typically used to replace a natural breast that has been removed, e.g. due to cancer, or to increase the size of a natural breast, when the natural size is considered unsatisfactory. In general, people who desire to change the overall size and shape of the breast implants after implantation have to undergo major surgery. It would be desirable for the patient to adjust the size and shape of the breast implant easily, depending on current needs. For instance, as time goes by the patient might no longer be happy with the size or shape of the artificial breast. Or, the patient might want to change the shape or size only temporarily. For instance, one might wish to reduce the volume of the breast implant during sports activities or one might wish to enlarge the size for a particular event, such as a formal evening affair.
U.S. Pat. No. 6,875,233 B1 discloses a breast implant which allows the overall size and shape thereof to be changed once it has been surgically implanted. Such breast implant includes an exterior shell and an inner bladder. The exterior shell is typically a bellows having a plurality of pleats, so that the outer size of the implant is variable. As the bladder is filled, the exterior shell expands in a manner that creates a lifting effect and a ballooning effect. A valve connected to both the exterior shell and the inner bladder can be used to fill the bladder external to the patient without the need for further surgery after the implant has been implanted in the patient. The bladder may be filled with a liquid, a gas or a solid, and such filler can be added and removed through the valve as needed. The valve either remains external, so that it can be used without any further surgery, or it can be located under the patients skin, in which case minor surgery must be performed to access the valve.
The options for changing the shape of this prior art breast implant are limited. Also, it is inconvenient for the patient that the valve for accessing the inner bladder of the breast implant permanently penetrates the patient's skin or, where it is implanted subcutaneously, requires minor surgery to be accessed.
US 2003/0074084 A1 discloses a breast implant with a plurality of chambers. The chambers are differently pressurized in order to control the shape of the breast implant upon inflation thereof. Each chamber may be provided with a pair of conduits for alternatively delivering fluid to and removing fluid from the chamber. Terminal connectors of such conduits can be easily located by medical practitioners for delivery of fluid to or removal of fluid from a desired chamber either manually or assisted by machinery. Alternatively, fluid can be supplied or removed by inserting a hollow needle directly into the chambers of the breast implants.
While the options of changing the shape of this prior art breast implant are improved over the breast implant disclosed in U.S. Pat. No. 6,875,233 B1, a medical practitioner is still needed to achieve different sizes and shapes of the breast implant after its implantation.
In a more simple embodiment described in US 2003/0074084 A1, one-way valves are each disposed between two adjacent chambers for enabling a transfer of fluid from a first to a second of the adjacent chambers upon application of an external compressive force to the first chamber. This way, the valves enable reshaping of the breast implant merely through manipulation. It is even suggested to automatically open and close the valves by wireless remote control.
While this embodiment would allow the shape of the breast implant to be changed non-invasively merely through manipulation, the size of the breast, i.e. the volume of the breast implant would not be affected thereby.
PCT/EP2009/000622 mentioned in the outset also relates to a breast implant system comprising a plurality of chambers which are interconnected when implanted such that fluid can be exchanged between them so as to change their respective fluid content. Various embodiments are disclosed for changing the shape but not the volume, for changing the shape and also the volume without a change of the breast implant's mass (this being achieved by causing a gas-filled chamber to be compressed when liquid is exchanged between chambers of the breast implant), and for changing the shape and also the volume of the breast implant involving a change of the breast implant's mass. It is further described that fluid exchange between the chambers can be achieved by manually compressing the one or the other fluid chamber, similar to the afore-mentioned US 2003/0074084 A1. However, preferred embodiments include a fluid reservoir implanted remote from the breast implant in the patient's abdominal cavity or inside the patient's chest area, such as outside the thorax under the minor pectoralis muscle or between the major and the minor pectoralis muscles. A pump may be provided for pumping the fluid between the chambers of the breast implant and/or between one or more chambers and the remotely implanted reservoir. The pump may be manually driven for which purpose it is advantageously implanted subcutaneously. Alternatively, the pump may be driven by a motor, which may likewise be implanted. Pump and/or motor may be driven by energy wirelessly transmitted from outside the patient's body. A control unit for controlling the entire process, in particular wirelessly, may be further provided. The breast implant may further have a rigid back plate, to which at least one chamber is fixedly connected, to provide stiffness giving the breast implant a basic contour which is maintained throughout any shape changes of the breast implant. Furthermore, in order to improve the overall appearance of the breast implant, the part of the breast implant's outer wall facing away from the patient's chest may comprise a compartment filled with a soft material, such as silicone.
Thus, the breast implant system disclosed in PCT/EP2009/000622 offers a great variety of options for changing the shape and the size of a breast implant after its implantation. The changes can be easily carried out and controlled by the patient without any medical practitioner being involved.
However, with these prior art breast implants the problem arises that upon changing the volume of one or more chambers within the breast implant and, thus, the shape and/or size of the implant, relative movement of mutually adjacent surfaces within the breast implant will occur. More specifically, the outer surface of a first chamber may contact the respective outer surface of a second chamber and/or may contact the afore-mentioned rigid back wall and/or the afore-mentioned flexible outer wall, within which the fluid chambers are held and which may form a silicone-filled compartment as mentioned. Relative movement between the contacting surfaces of one or more of the afore-mentioned elements causes a substantial amount of surface friction which has to be overcome in order to achieve the size and/or shape variation in the desired manner. When the fluid exchange is achieved by locally compressing the breast implant manually or by compressing e.g. a subcutaneously implanted reservoir, the patient has to apply relatively high compressing forces. Where the exchange of fluid is achieved with the aid of an implanted motor, the motor must be relatively strong. In other words, such motor is relatively voluminous and needs much energy, both aspects not being desired for parts to be implanted in a patient's body.